Methods to reduce stress on a metal interconnect

Abstract

Semiconductor devices and methods of fabricating semiconductor devices are disclosed. A disclosed semiconductor device comprises: a semiconductor substrate; an uppermost metal interconnect formed on the semiconductor substrate; an oxide layer formed on the substrate and the uppermost metal interconnect; an aluminum layer formed on the oxide layer; and a stress-relief layer formed on the aluminum layer to thereby prevent cracking of the passivation layer during a subsequent packaging process, to increase reliability of the passivation layer, and to prevent degradation of properties of the semiconductor device.

1. A method to fabricate a semiconductor device, the method comprising:
 forming an uppermost metal interconnect on a semiconductor substrate;  
 forming an oxide layer on the substrate and the uppermost metal interconnect;  
 forming an aluminum layer on the oxide layer; and  
 forming a stress-relief layer on the aluminum layer to reduce stress on the metal interconnect.  
 
   
   
     2. A method as defined in  claim 1 , wherein forming the stress-relief layer comprises:
 performing a plasma treatment on a surface of the aluminum layer to form an aluminum oxide layer; and  
 annealing the aluminum oxide layer.  
 
   
   
     3. A method as defined in  claim 2 , wherein the plasma treatment uses at least one of N 2 O gas and O 2  gas. 
   
   
     4. A method as defined in  claim 3 , wherein the aluminum oxide layer is annealed in an atmosphere of inert gas. 
   
   
     5. A method as defined in  claim 3 , wherein the aluminum oxide layer is annealed in an atmosphere of gas including at least one of N 2 O, O 2 , N 2 , and H 2 . 
   
   
     6. A method as defined in  claim 2 , wherein the annealing is performed at a temperature of 200 to 400. 
   
   
     7. A method as defined in  claim 2 , wherein the aluminum oxide layer is annealed in an atmosphere of inert gas. 
   
   
     8. A method as defined in  claim 7 , wherein the inert gas is at least one of Ar and He. 
   
   
     9. A method as defined in  claim 2 , wherein the aluminum oxide layer is annealed in an atmosphere of gas including at least one of N 2 O, O 2 , N 2 , and H 2 . 
   
   
     10. A method as defined in  claim 1 , wherein the semiconductor device is at least one of a multi-interconnect adapted device and a power device.